This invention relates to a tracking device using GPS, preferably for use with vehicles although it would also be suitable for other moving objects.
The reduction in price of global position system (GPS) receivers and the improved position accuracy available from GPS since selective availability (SA) was removed in April 2000, has fostered the use of onboard GPS receivers to track the position of vehicles.
In some instances the vehicle position so determined is used by the vehicle operator or other equipment located in the vehicle. In other applications the vehicle position information is transmitted to a central control location in order to provide remote tracking of the vehicle for fleet management. Existing mobile radio systems, such as the mobile cellular telephone system, have been proposed to communicate the GPS position data from the vehicle to the central control station. A tracking system which uses a speech synthesiser interface between a GPS receiver and a cellular telephone is disclosed in U.S. Pat. No. 5,918,180. A direct connection between the GPS receiver and a radio transceiver using a modem is clearly to be preferred.
The desirability of an integrated antenna for both cellular and GPS use has been recognised. Allen Telecom provide such a vehicle mounted antenna under the trade mark Tele-Locator(trademark).
In many applications, for example fleet vehicle position and activity tracking where there is no vehicle operator interface required, it is undesirable and inconvenient to incorporate GPS equipment and separate discrete cellular telephone equipment within the vehicle operator cab. It would be desirable to integrate not only the antennas, but all GPS equipment and radio transceiver equipment in a package adapted for exterior mounting on the vehicle.
It is an object of the present invention to provide onboard vehicle tracking apparatus which meets the above desiderata.
Accordingly in a first aspect the invention consists in a vehicle tracking apparatus comprising:
a GPS receiver,
a processor which receives and stores vehicle position data from said receiver,
a radio transmitter activated by said processor and modulated with at least the vehicle position data stored by said processor,
a GPS antenna and a radio antenna configured and juxtaposed such that physical and radio interference between said antennas is minimised,
a waterproof housing adapted for mounting on the exterior of a vehicle in which all of the above components are mounted, and
said apparatus requiring only an external source of power to operate.
In a second aspect the invention consists in a vehicle tracking apparatus comprising:
a GPS receiver,
a radio transmitter activated by said processor and modulated with at least the vehicle position data provided by said GPS receiver,
a GPS antenna and a radio antenna configured and juxtaposed such that physical and radio interference between antennas is minimised, and
a waterproof housing adapted for mounting on the exterior of a vehicle or other mobile object in which all of the above components are mounted.
The vehicle tracking apparatus of the present invention is contained in a low profile streamlined weatherproof enclosure or dome purpose-designed for mounting on an exterior surface of a vehicle such as the roof. The GPS receiver, a processor, and a radio transceiver (such as cellular telephone componentry) are all mounted within the enclosure. The apparatus is self-contained and requires only a dc supply from the vehicle to operate. However where vehicle activity other than vehicle position is to be monitored, connections need to be made to other transducers mounted in the vehicle, for example, the vehicle ignition circuit.
Vehicle activity data is captured and stored at regular intervals and this data is then communicated via a radio network to a computer at the monitoring station. Software in this computer provides plots of monitored vehicles and other activity for each vehicle such as ignition on/off times, speed, direction and distance travelled.
In the preferred embodiments of the invention the radio system used is one of the established cellphone networks and references hereafter will be confined to such networks.